Calculated Cetane Index for distillate marine fuels using ASTM D976 four-variable formula - a surrogate for DCN / cetane number when no engine test is available.
Formula
$$ CI = 45.2 + 0.0892 T_{10} + (0.131 + 0.901 G) T_{50} + (0.0523 - 0.420 G) T_{90} + 0.00049 (T_{10}^2 - T_{90}^2) $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $T_{10},T_{50},T_{90}$ | Distillation recovery temperatures | °C | ASTM D86 |
| $G$ | API gravity / 100 | - | D1298 density |
Sources
- ASTM D976.